Login or Register to Ask a Question and Join Our Community


Gentoo

Linux FAQ Items

 
Thread Tools Search this Thread
Operating Systems Linux Gentoo Linux FAQ Items
Prev   Next
# 8  
Old 09-10-2006
Tools Linux FAQ Items
Hello Guys,

Sometimes it is necessary to add more swap space after installation. For example, you may upgrade the amount of RAM in your system from 64 MB to 128 MB, but there is only 128 MB of swap space. It might be advantageous to increase the amount of swap space to 256 MB if you perform memory-intense operations or run applications that require a large amount of memory.

You have two options: add a swap partition or add a swap file. The easiest way to achieve this it to through swap file.

To add a swap file:


Determine the size of the new swap file and multiple by 1024 to determine the block size. For example, the block size of a 64 MB swap file is 65536.

At a shell prompt as root, type the following command with count being equal to the desired block size:

dd if=/dev/zero of=/swapfile bs=1024 count=65536

then

mkswap /swapfile

To enable the swap file immediately but not automatically at boot time:

swapon /swapfile

To enable it at boot time, edit /etc/fstab to include:

/swapfile swap swap defaults 0 0


The next time the system boots, it will enable the new swap file.

After adding the new swap file and enabling it, make sure it is enabled by viewing the output of the command cat /proc/swaps or free.

bingo Smilie

Let me know if you have any questions.

Prashant,
prashant ohol - System Administrator,
Last edited by prashant_ohol; 09-11-2006 at 04:50 PM..
 
Login or Register to Ask a Question

Previous Thread | Next Thread

3 More Discussions You Might Find Interesting

1. Post Here to Contact Site Administrators and Moderators

Dead link in FAQ

Dead link from FAQ, then Technical FAQ: Senior Advisor - https://www.unix.com (Was about to suggest that a O/P read this FAQ). (9 Replies)
Discussion started by: methyl
9 Replies

2. Shell Programming and Scripting

awk between items including items

OS=HP-UX ksh The following works, except I want to include the <start> and <end> in the output. awk -F '<start>' 'BEGIN{RS="<end>"; OFS="\n"; ORS=""} {print $2} somefile.log' The following work in bash but not in ksh sed -n '/^<start>/,/^<end>/{/LABEL$/!p}' somefile.log (4 Replies)
Discussion started by: Ikon
4 Replies

3. Post Here to Contact Site Administrators and Moderators

Unix for Dummies FAQ

I have created a small FAQ for the "Unix for Dummies" forum. Hopefully this will be useful, as there are questions which are asked (and answered) repeatedly. <A HREF="http://www.droflet.net/unix_dot_com_faq.html">http://www.droflet.net/unix_dot_com_faq.html (0 Replies)
Discussion started by: PxT
0 Replies
Login or Register to Ask a Question

LEARN ABOUT DEBIAN

dphys-swapfile

DPHYS-SWAPFILE(8)					      System Manager's Manual						 DPHYS-SWAPFILE(8)

NAME

       dphys-swapfile - set up, mount/unmount, and delete an swap file

SYNOPSIS

       dphys-swapfile setup|swapon|swapoff|uninstall

DESCRIPTION

       dphys-swapfile  computes  the size for an optimal swap file (and resizes an existing swap file if necessary), mounts an swap file, unmounts
       it, and and delete it if not wanted any more.

OPTIONS

       There is only one parameter, an command, which can be either of these:

       setup  Tells dphys-swapfile to compute the optimal swap file size and (re-)generate an fitting swap file. Default it 2 times RAM size. This
	      can be called at boot time, so the file allways stays the right size for current RAM, or run by hand whenever RAM size has changed.

       swapon and  swapoff These run the swapon and swapoff commands on the swapfile. Note that direct swapon/off from /etc/fstab is not possible,
	      as that is (at least on Debian) done in the same script that mounts /var (which is where the swap file most likely resides). And	we
	      need to do our setup between those actions. So pass up /etc/fstab, and do our own swapon/off.

       uninstall
	      Gets rid of an unwanted swap file, reclaiming the disk space.

CONFIG

       The config file /etc/dphys-swapfile allows the user to set up the working environment for dphys-swapfile.

       This config file is a sh script fragment full of assignments, which is sourced. Standard sh syntax rules apply. Assignments are:

       CONF_SWAPFILE
	      Set  where  the swap file should be placed. Defaults to /var/swap. It is unlikely that you will need to change this, unless you have
	      very strange partitioning, and then you will most likely be using an swap partition anyway.

       CONF_SWAPSIZE
	      Force file size to this. Default is 2*RAM size. This is unlikely to be needed, unless in strange	diskspace  situations.	Note  that
	      swap enabled and smaller than RAM causes kernal-internal VM trouble on random systems.

       CONF_SWAPFACTOR
	      Set the relation between RAM and swap size. Must be an integer. Defaults to 2 which means swap size = 2 * RAM size

       CONF_MAXSWAP
	      Set  maximum  size of the swap file in MBytes. Defaults to 2048 which was the former kernel limit for the swapfile size and is now a
	      limit to prevent unusual big swap files on systems with a lot of RAM.

FILES

       /etc/dphys-swapfile
	      user config

       $CONF_SWAPFILE
	      the swap file, target of the whole action (defaults to /var/swap)

EXAMPLES

       dphys-swapfile is usually run at system startup and shutdown from an /etc/init.d (or /etc/rc.d) script, such as this (minimal) one:

       #!/bin/sh
       # /etc/init.d/dphys-swapfile - automatically set up an swapfile
       # author franklin, last modification 2004.06.04
       # This script is copyright ETH Zuerich Physics Departement,
       #   use under either modified/non-advertising BSD or GPL license
       case "$1" in
	 start)
	   /sbin/dphys-swapfile setup
	   /sbin/dphys-swapfile swapon
	   ;;
	 stop)
	   /sbin/dphys-swapfile swapoff
	   ;;
       esac
       exit 0

       If an sysadmin wants to have his swapfile in annother place, say /var/run/swap, he can use:

       In /etc/dphys-swapfile:

       CONF_SWAPFILE=/var/run/swap

AUTHOR

       franklin@phys.ethz.ch, http://www.phys.ethz.ch/~franklin/

D-PHYS Swapfile Tools						    2006.09.15							 DPHYS-SWAPFILE(8)